Dating from 1946, this film shows some of the planning that went into the Operation Crossroads nuclear test series, to ensure that personnel were not exposed to dangerous levels of radiation and radioactive fallout resulting from the bomb explosions. This included the use of drone aircraft to fly through the atomic cloud, and extensively monitoring throughout the target area. Unfortunately the measures taken proved insufficient and in reality, many personnel may have suffered exposure as a result of the test, resulting in an average shorter lifespan of three months for participants.
Operation Crossroads was a series of two nuclear weapon tests conducted by the United States at Bikini Atoll in mid-1946. They were the first nuclear weapon tests since Trinity in July 1945, and the first detonations of nuclear devices since the atomic bombing of Nagasaki on August 9, 1945. The purpose of the tests was to investigate the effect of nuclear weapons on warships.
The Crossroads tests were the first of many nuclear tests held in the Marshall Islands, and the first to be publicly announced beforehand and observed by an invited audience, including a large press corps. A fleet of 95 target ships was assembled in Bikini Lagoon and hit with two detonations of Fat Man plutonium implosion-type nuclear weapons of the kind dropped on Nagasaki, each with a yield of 23 kilotons of TNT (96 TJ).
The first test was Able. The bomb was dropped from the B-29 Superfortress Dave’s Dream of the 509th Bombardment Group on July 1, 1946, and detonated 520 feet (158 m) above the target fleet. It caused less than the expected amount of ship damage because it missed its aim point by 2,130 feet (649 m). The second test was Baker. The bomb, known as Helen of Bikini, was detonated 90 feet (27 m) underwater on July 25, 1946. Radioactive sea spray caused extensive contamination. A third deep water test, Charlie, planned for 1947, was canceled primarily because of the United States Navy’s inability to decontaminate the target ships after the Baker test. Ultimately, only nine target ships were able to be scrapped rather than scuttled. Charlie was rescheduled as Operation Wigwam, a deep water shot conducted in 1955 off the California coast.
Bikini’s native residents agreed to evacuate the island, with most moving to the Rongerik Atoll. Later, in the 1950s, a series of large thermonuclear tests rendered Bikini unfit for subsistence farming and fishing. Because of radioactive contamination, Bikini remains uninhabited as of 2013, though it is occasionally visited by sport divers. Although planners attempted to protect participants in the Operation Crossroads tests against radiation sickness, one study showed that the life expectancy of participants was reduced by an average of three months. The Baker test’s radioactive contamination of all the target ships was the first case of immediate, concentrated radioactive fallout from a nuclear explosion. Chemist Glenn T. Seaborg, the longest-serving chairman of the Atomic Energy Commission, called Baker “the world’s first nuclear disaster.”
All Operation Crossroads operations were designed to keep personnel from being exposed to more than 0.1 roentgen (R) per day. At the time, this was considered to be an amount of radiation that could be tolerated for long periods without any harmful effects on health. Since there was no special clothing or radiation shielding available, the protection plan relied on managing who went where, when, and for how long.
Radioactively “hot” areas were predicted in advance, and then checked with Geiger counters, sometimes by remote control, to see if they were safe. Of the total mass of radioactive particles scattered by each explosion, 85% was unfissioned plutonium which produces alpha radiation not detected by film badges or Geiger counters. There was no method of detecting plutonium in a timely fashion, and participants were not monitored for ingestion of it.
In 1996, a government-sponsored mortality study of Operation Crossroads veterans showed that, by 1992, 46 years after the tests, veterans had experienced a 4.6% higher mortality than a control group of non-veterans. The mortality increase was higher, 5.7%, for those who boarded target ships after the tests than for those who did not, whose mortality increase was only 4.3%.
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This film is part of the Periscope Film LLC archive, one of the largest historic military, transportation, and aviation stock footage collections in the USA. Entirely film backed, this material is available for licensing in 24p HD and 2k. For more information visit http://www.PeriscopeFilm.com
